How can I find the php.ini file used by the command line?

I need to enable pdo_mysql in my EasyPHP environment, so I went to the php.ini file and uncommented the following line:

extension=php_pdo_mysql.dll

Unfortunately I still have the same problem.
I’m using the CLI so I suppose I need to locate the php.ini file used by the CLI. How can I find it?

Just run php --ini and look for Loaded Configuration File in the output for the location of php.ini used by your CLI.